Hollow Notched K-Wires for Bone Drilling With Through-Tool Cooling.

Kirschner wire (K-wire) is a common tool in clinical orthopedic surgery for bone fracture fixation. A significant amount of heat is generated in bone drilling using K-wires, causing bone thermal necrosis and osteonecrosis. To minimize the temperature rise, a hollow notched K-wire in a modified surgical hand drill with through-tool cooling was developed to study the bone temperature, debris evacuation, and material removal rate. The hollow notched K-wire was fabricated by grinding and micro-milling on a stainless steel tube. Bone drilling tests were conducted to evaluate its performance against the solid K-wires. Results showed that compared with solid K-wires, hollow notched K-wire drilling without cooling reduced the peak bone temperature rise, thrust force, and torque by 42%, 59%, and 62% correspondingly. The through-tool compressed air reduced the peak bone temperature rise by 48% with the forced air convection and better debris evacuation. The through-tool water cooling decreased the bone temperature by only 26% due to accumulation and blockage of bone debris in the groove and channel. This study demonstrated the benefit of using the hollow notched K-wire with through-tool compressed air to prevent the bone thermal necrosis. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2297-2306, 2019.